Always listening for the enemy: Heinz Hoenig as Maat the sonar operator in the 1981 war epic Das Boot.

"It is on official record that a certain ship belonging to one of our great allies chased a sperm whale for - I forget how many miles. The chase was by hydrophone, aural, and did not become visual until many miles had been run, when the hydrophone experts were reluctantly compelled to admit that their legs had been pulled, or at any rate their ears tweaked. They state the fact that the sperm whale faithfully reproduced the sound of a U-boat running on electric motors throughout the entire chase." [Hush; or The Hydrophone Service, 1920 by H.W. Wilson]

Candace Hilligoss as the church organist Mary Henry in the fantastic Carnival of Souls [1962]. This image comes from a remarkable scene in which Mary suddenly finds herself thrown into a world of silence. All that remains in the soundtrack are the sound of Mary's lonely footsteps against the haunting musical backdrop of composer Gene Moore's organ.

"It was more than just not being able to hear anything, or make contact with anyone, it was as though, as though for a time I didn't exist. As though I had no place in the world. No part of the life around me." - Mary Henry to Dr. Samuels.

The Signal and Noise playlist is now complete. Comprising of 50 short excerpts of sound and music, the collection brings together a wide range of material recorded in the UK, Japan and Indonesia from the period 2002 up to 2016.

One of my personal favourites is North India Bells from 2008. A montage of bells recorded at different times, in different locations across North India. The ringing of bells together with the incessant noise of traffic - these are my two lasting sound memories of the subcontinent. Other field recording highlights include gamelan recordings made in Java and Bali (particularly the Mangkunegaran Karawitan excerpt) as well as a few interesting sounds from the Japanese countryside and urban environments. Various textures falling under the vague descriptive tag 'ambient' or 'drones' pepper the playlist. Of these pieces Sputnik [2016], Tokai [2006] and Theme for Mysterious Semblance [2013] seem to provide floaty musical respite, lieing somewhere in the domain of Brian Eno or William Basinski. While 'noise' favourites of mine would be the Xenakis-inspired Concret Sferics [2011] piece (here in its 2-minute entirety), Merzinvaders [2016] and the rather simple refrain of Metal on Turntable [2014].

Sound as mystery: Valérie Mairesse, Allan Edwell and Erland Josephsonlistening in Tarkovsky's final film The Sacrifice [1986].

Robert Bresson once said in an interview: “We must let the mystery remain. Life is mysterious, and we must see that on screen. The effects of things must always be shown before their causes, like in real life.”

Sound for Tarkovsky is a mysterious force. A device to help express different plains of reality - the inner caverns of the mind, the material world, nature and the spiritual plain. In film as in life it moves in mysterious ways. Like a gas, sound diffuses in and out of our field of vision, within and beyond the frame of the camera. In doing so it leads us to question the nature of our reality, of our very existence: Where are we? What force is at work here? Sound itself is both that of a physical body and of spirit. Something of this and of another world. Andrea Truppin in her inspiring essay And Then There Was Sound: The Films of Andrei Tarkovsky (1992) talks about "sound's potential for ambiguity and abstraction" and how this is deployed by the director to evoke the existence of unseen objects and to penetrate into the invisible spiritual world. Truppin writes: "Allowing a sound source to remain a figment of our imagination, mystifying rather than orienting, subverts sound's traditional role in film."

When it comes to electronic sounds, nothing beats the pure bite of dedicated hardware oscillators: Excerpt of Sputnik - part of the ongoing Signal and Noise collection. Thanks go to Tom Andrews for supplying the raw material.

I recently setup a playlist of short sound and music excerpts from past and present projects called Signal and Noise. An online home of sorts for sonic odds and ends recovered from the digital archives.

The latest upload is an excerpt from a recording I made in London in 2015 of a crazy free-jazz overblowing garbage truck in West London. Somewhere between the sound of the 1954 Godzilla and the outer-planetary sax explorations of Pharoah Sanders.

Thus we are approaching noise-sound. This revolution of music is paralleled by the increasing proliferation of machinery sharing in human labor. In the pounding atmosphere of great cities as well as in the formely silence countryside, machines creat today such a large number of varied noises that pure sound, with its littleness and its monotony, now fails to arouse any emotion. [Art of Noise, 1913 - Luigi Russolo]

Every once in awhile I'm able to flee the isolation of the studio and venture out into the real world in search of new noises. Last week was one such an occasion when sound designer John Cohen and myself travelled to Wanborough village just outside Swindon to record the sounds of several Victorian and Edwardian-era traction engines. We managed to capture a whole range of hisses, creaks, clangs and chugging mechanical rhythms that would have made Russolo proud - a soundscape of an altogether more industrial age.

"Everything audible from all over the world becomes material" - Ruttmann, Film Kurier, 1929

Weekend [1930] - extract of score • www.medienkunstnetz.de

Walter Ruttmann [1897-1941] was a German filmmaker best known perhaps for his 1927 city symphony film Berlin: Symphony of a Metropolis. Three years later he created Weekend, an image-less experimental film using sounds he recorded around Berlin.